<style>
    #loading{
        /*height: 80px;*/
        width: 100%;
        position: absolute;
        /*top: 40%;*/
        margin-top: -35px;
        text-align: center;
    }
</style>
<div class="ibox-content" id="loading" style="background:none;z-index:-1">
    <div class="spiner-example">
        <div class="sk-spinner sk-spinner-three-bounce">
            <div class="sk-bounce1"></div>
            <div class="sk-bounce2"></div>
            <div class="sk-bounce3"></div>
        </div>
    </div>
</div>